George Anthony: Caylee OD'd after Casey drugged her

George Anthony believes Caylee Anthony overdosed after her mother, Casey, tried to sedate her so she could go out and party. His wife and Casey's mother, Cindy, doesn't agree.

In a shocking (or not-so-shocking) twist, George Anthony, grandfather of Caylee Anthony, blamed his daughter Casey for the toddler's death during an interview on the "Dr. Phil" show.

George Anthony said he believed Casey drugged Caylee so she could go out and party.

"Yeah I blame my daughter for Caylee not being here today," George Anthony said. "I believe she was there and I also believe she probably had some help."

Casey Anthony was acquitted this summer of murder charges in the death of Caylee. During her dramatic trial, Casey claimed Caylee accidentally drowned in the family pool.

"I buy the part that Caylee drowned but I don't buy the circumstances surrounding the drowning," said Casey's mother, Cindy Anthony, during the interview.

She seemed surprised, though, to hear her husband's theory.

"Inside of my heart, I don't believe that Caylee drowned…I believe there's something else that happened to her…I believe that Casey or someone else that she was with possibly gave too much to Caylee...she fell asleep and didn't wake up," George Anthony said.

"This is the first time that I've heard this out of his mouth," Cindy Anthony said. "I don't buy that for a moment. I'm sorry. We disagree about this. ... I'm really kind of shocked to hear that today."